Frictional clutches, such as those used in motorized vehicles, tend to generate an enormous amount of heat when their clutch packs are engaged. In order to dissipate this generated heat, cooling oil is routed to the clutch chamber at relatively low pressure. During the disengagement process however, it is advantageous to minimize the amount of cooling oil which is retained in the clutch chamber so as to reduce the drag on the clutch and thereby improve its overall efficiency. Traditionally, control of the flow of cooling oil to the clutch has been accomplished by the use of spring operated poppet or spool valves. The disadvantages of using such valves is that they require a plurality of components, they necessitate the costly machining of valve bores and seats, and their physical appearance requires an increase in the overall diameter and/or length of the clutch.
Now a centrifugally actuated cooling oil cut-off valve has been invented which overcomes the disadvantages and deficiencies of the prior art.